Spring loaded socket and flexible contact



July 26, 1966 n-z GERAFD 3,263,204

SPRING LOADED SOCKET AND CONTACT Filed May 21, 1964 2 Sheets-Sheet 1 E. F122 Gerald,

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SPRING LOADED SOCKET AND FLEXIBLE CONTACT Filed May 21, 1964 2 Sheets-Sheet 2 P8 6 Ma 2? a0 ?2 lave afar.

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United States Patent 3,263,204 SPRING LOADED SOCKET AND FLEXIBLE CONTACT Robert E. FitzGeraid, Quincy, Mass., assignor to United- The present invention relates generally to lamp sockets and more specifically to a contact insert for lamp sockets.

An object of the present invention is to provide a base insert for lamp sockets having flexible leaf spring contacts engaged therewith.

A further object of the present invent-ion is to provide a base insert for lamp sockets having flexible spring contacts as means of adjusting for variations in the solder ball connections on a lamp bulb.

A serious problem in multiple filament bulbs is the placing of the major filament at the plane on Which the focal point of the bulbs optical system lies. In the conventional system, the position of the major filament is frequently dictated by the position of the J-slots of the socket alone. One of the improvements presented by the present invention is that the positioning of the major filament is provided by the upper surface of the channeled insert and the flexing of the leaf spring contacts working co-operatively in relation to the bulb as will be more fully set out hereinafter. Furthermore, the spring action of the contacts provides a means of adjusting for variations in height of the solder ball contacts of the bulb.

in the drawings:

FIG. 1 is a top plan view of the socket;

FIG. 2 is a section taken on line 2-2 of FIG. 1;

FIG. 3 is a top plan view of the base portion of the insert;

FIG. 4 is a top plan view of the cap portion of the insert;

FIG. 5 is a section similar to that shown in FIG. 2 showing a bulb engaged;

IFIG. 6 is a section taken on line 6-6 of FIG. 5;

FIG. 7 is a cross sectional view of the shell unit of a variation of the socket shown in FIGS. 1-6;

FIG. 8 is a section of the insert of the variation; and

FIG. 9 is a section of the shell unit engaged with the insert of the variant with the contact and lead shown in full.

There is shown in the drawings a lamp socket having an outer shell 10, an inner shell 12, a helical compression spring 14, an insert 16 and a pair of leaf contacts 1 8 and 20. The outer shell 10 may be formed of a metal or plastic material and comprises a tubular body portion open at both ends and having an integral circumferential flange 24 extending in right angle relationship therewith. The external flange 24 integrally connects the upper part of the outer shell 10 with an intermediate part. The intermediate part has greater internal and external diameters than the upper part. The top surface of the flange 24 is thereby longer than the lower surface of the same providing an internal shouder 26. The lower part of the body portion is connected integrally 'with the intermediate part remote from the upper part by a diverging circumferential land 28. The lower part has greater internal and external diameters than the intermediate part of the outer shell 10.

The tubular inner shell 12 comprises an upstanding tubular wall portion open at both ends and an integral circumferential flange 30 extending outwardly from the wall portion adjacent one of the open ends. The flange 30 has a pair of tabs 27 extending from opposite sides thereof as indicated in FIGS. 2 and 5.

3,263,204 Patented July 26, 1966 The insert 16 comprises a circular portion 32 and two integral extensions. The insert 16 is assembled by placing a cap portion 34 and a base portion 36 into engagement along a mutual plane as shown in FIGS. 2 and 5. The circular portion 32 includes an upstanding wall 38 defining an opening which is separated into two semicircular openings or wells 40 by a bar of bridging element 42 as shown in FIG. 1. The upper surface of the assembled bar element 42 lies on the same plane as the upper surface of the upstanding wall 38. The two tubular extensions which protrude from the circular portion 32 comprise a short extension 44 and a longer extension 46.

The portion of the short extension 44 supplied by the base portion 36 includes a rectangular stud 48 which protrudes upwardly from its base as shown in FIG. 3 for a purpose to be described hereinafter. The portion of the longer extension 46 supplied by the base portion 36 includes a portion of smaller annular internal diameter to form a shelf 50 spaced from the end of the extension 46 as shown in FIG. 3. A shallow groove 52 is formed along each portion of the upper surface of the part of the longer extension 46 supplied by the base portion 36 as shown in FIG. 3. The grooves 52 are in spaced parallel relation to each other and the axis of the larger extension 46. A pair of ribs (not shown) extend from the surfaces of the portion of the longer extension 46 supplied by the cap portion 64 to mate with their respective grooves 52 on engagement of the two parts. Each of the extensions 44 and 46 opens into the semicircular well 40 on its side of the insert 16 as indicated in FIG. 3.

The leaf contacts 18 and 20 are for the most part similar in construction although there are certain specific structural differences. Generally speaking, they comprise a tubular portion open at both ends and a flat spring leaf 58 integral with the bottom of the tubular portion arced upwardly to a plane above the upper surface of the tubular portion and then bent in a shallow arc while extend ing away from the tubular portion on a plane generally parallel with the axis of the tubular portion as shown in FIGS. 2 and 5. The leaf contacts 18 and 20 are formed of a material which is capable of conducting electrical current. The variations in the two leaf contacts 18 and 20 are found first in the fact that the contact 20 is longer than the other and second in the fact that the end of the contact 20 at a point remote from its leaf spring 58 is formed into a bullet terminal to engage a contact channel in a plug (not shown). The plug (not shown) would also carry a bullet terminal to engage the shorter leaf contact 18 within its tubular portion.

The insert 16 is assembled with the leaf contacts 18 and 20 by placing the longer leaf contact 20 into the portion of the shorter extension 44 supplied by the base portion 36 of the insert 16 prior to assembly with the cap portion 34. To facilitate this engagement the rectangular stud 48 is inserted into a slot formed in the tubular body of the longer leaf contact 20. The bullet end of the leaf contact 20 extends beyond the short extension 44 to the plane of the terminal end of the longer extension 46. The shorter leaf contact 18 is placed within the portion of the longer extension 46 supplied by the base portion 36 on to the shelf 50 with the free end of the tubular portion of the same horizontal plane as the edge of the shelf 50 closest to the end of the laregr extension 46. Each of the spring leaves 58 of the leaf contacts 18 and 20 protrude into its respective half of the circular portion 32 provided by the base portion 36. The part of the circular portion 32 supplied by the cap portion 34 is provided with a sloping external engagement shoulder 60 as shown in FIGS. 4 and 6. The cap portion 34 then continues with an external wall in spaced relation to the axis of the circular part circumscribing an external circumference of less diameter than the receiving portion of the circular part. After both the leaf contacts 18 and 28 have been placed in their proper extension the cap portion 34 is placed into engagement with and on top of the base portion 36. Grooves and ribs may be placed to co-operate with each other to provide a better mating engagement of the two parts as set forth hereinbefore. When the assembly is complete, the spring leaf 58 of the leaf contacts 18 and 20 lie partially within the areas defined by the semicircular wells 40 and their upper arced surfaces extend above the plane of the top surface of the circular portion 32 as shown in FIG. 2.

The socket is assembled by first dropping the helical spring 14 into the outer shell 10 until it rests on the internal shoulder 26. The diameter described in the spring 14 is less than the internal diameter described by the shoulder 26. A pair of shallow grooves 62 are formed on the inside wall of the outer shell 10 from the land 28 to the plane of the external flange 24 and on opposite sides of the outer shell 10 as shown in FIGS. 2 and 5. The tabs 27 of the inner shell 12 have a width slightly less than the width of the grooves 62. The tabs 27 are fitted within the grooves 62 and the inner shell 12 is slid within the outer shell 10 until the flange 36 abuts the spring 14. The assembled insert 16 is then placed within the larger open end of the outer shell 10 until the engagement shoulder 60 of the cap portion 34 is in abutting relationship With the circumferential land 28 of the outer shell 10. An opening is provided in the outer shell 10 whereby the extensions 44 and 46 of the insert protrude beyond the periphery of the outer shell 10 as shown in FIGS. 1, 2 and 5. The free terminal end of the outer shell 10 may now be crimped over and into abutting engagement with the lower surface of the base portion 36 of the insert 16 thereby securely holding the insert 16 in engagement with the assembled socket.

The bulb 78 having studs for engagement with J-slots formed in the inner wall of the inner shell 12 and having a pair of solder ball connections 80 is engaged in the socket in a conventional manner. However, the difference is that when the solder ball comes into superposed abutting relationship with the leaf springs 58, the leaf springs would flex downward until the base of the bulb comes in close proximity to the upper surface of the bridging element 42.

The variant shown in FIGS. 7, 8 and 9 discloses an assembled shell unit and an insert, which can be engaged together subsequent to their individual assembly.

The insert 16a is similar to the insert 16 except that the cap portion 34a has an external circumferential groove 64 formed in it for engagement with a lip 66 formed in a housing 70. A circumferential ramp 68 is formed adjacent the grove 64 and is somewhat flexible for purpose to be described hereinafter.

The tubular housing 70 of the variant is open at both ends and has a converging inner circumferential shoulder 72 spaced from the end providing the lip 66. The spring 14a of the variant is similar to the spring 14 of the first construction and the inner shell 12a is similar to the inner shell 12. The variant is also provided with a shell element 74 having an integral annular flange 76 extending away from the axis of the shell element 74 adjacent an opening thereof.

The shell unit is assembled in the following manner. The inner shell 12a is dropped within the housing with the tabs 27a sliding within the grooves 62a, formed in the inner wall of the housing 70, until the flange 30a abuts the engagement shoulder 72. The spring 14a is then dropped in between the inner shell 12a and the housing 78 into abutting relationship with the flange 30a. The shell element 74 is then placed against an outwardly bent portion 78 which provides a circumferential flange at the opening in the housing 70 opposite to that provided by the lip 66. This outwardly extending circumferential portion 78 can then be clamped over the annular flange 76 of the shell element 74 completing the assembly of the shell unit as shown in FIGS. 7 and 9. The lip 66 can then be pressed against the ramp 68 which will give way and allow the lip 66 to engage within the groove 64 of the insert 16a thereby completing the assembly of the insert and the shell unit.

While there has been illustrated and described a preferred embodiment of the invention, it should be understood that the invention is best described by the following claim.

What is claimed:

A lamp socket, including a tubular outer shell open at both ends, an inner tubular shell, also open at both ends, said inner shell having an integral circumferential flange, extending therefrom adjacent one of said openings, said flange having at least one tab extending therefrom and means formed on said outer shell for engaging said tabs, a helical compression spring engaged with said inner shell aligned between said inner shell and said outer shell and in abutting relation with said flange, an

insert engaged with said outer shell at one of its open ends, said insert including an insulating housing having a circular portion of at least two integral extensions extending therefrom, one of said extensions being shorter than the other, and two contacts, each of said contacts having a tubular portion and an integral flexible leaf spring extending therefrom, each of said tubular portions of said contacts being circumscribed by at least a portion of one of said extensions and each of said flexible leaves extending partially within a component, formed in a circular portion by at least one rib, and a portion of each of said leaves extending above the plane of said housing and within the area defined by said outer shell.

References Cited by the Examiner UNITED STATES PATENTS 1,978,115 10/1934 Roper 33918l X 2,127,675 8/1938 Clements 339l88 FOREIGN PATENTS 528,943 11/1940 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

W. DONALD MILLER, Examiner. 

